Higher:
Explain what factors can affect a chemical change
Middle:
Understand the process of how a chemical change happens
Lower:
Know what a chemical change is
Lesson Recap Starter: Think back to the last lesson. Discuss with your talk partner why some changes to materials are not reversible.
Lesson Starter: What is water made out of? Think, Pair, Share and write your suggestion down on a sticky note or mini-whiteboard.
Use slide to help children visualise the question - Why does a chemical change alter a molecule permanently?
Children to use sticky notes / mini whiteboards to suggest an answer.
presentation - starter slide
sticky notes
mini whiteboard
Answer questions and take part in activities during the presentation.
Key Concept:
During this unit, each lesson contains a key concept question housed in the '30 Second Challenge' slide. To help children master this content so the knowledge moves from their short term memory to their long term memory, at the beginning of the follow on lesson the question from the previous lesson is revisited.
The questions covered during this unit include:
1. Explain the difference between filtering, sieving and evaporating.
2. Explain what happens when a substance is dissolved. What does saturated mean?
3. Discuss with your talk partner why some changes to materials are not reversible.
4. What are permanent chemical changes?
5. What's the difference between physical and chemical change?
6. What is the difference between elements, compounds and mixtures?
presentation
Expert Film: Jared explores Chemical Changes which are fast and slow.
Expert Film: Prof. Mark Searcey from the UEA talks to Dr Sam Rowe about making peptides.
How we deliver the Gatsby Benchmarks:
2 - Learning from career and labour market information: Pop along to Developing Experts career’s zone to find out about jobs in your area.
4 - Linking curriculum learning to careers: This unit showcases careers that relate to changes to materials. Access our 360° virtual work tours.
7 - Encounters with Further and Higher Education: Pop along to Developing Experts career’s zone to find out about training providers in your area.
Presentation - Expert film
Chemical Changes
Using the Handout the children are to look at the different pictures and say which ones show temporary changes, which show permanent changes, and write about how each has changed.
Children can choose one of the chemical changes and see what variables can affect the rate or type of chemical change.
i.e. with rusty nails, does the temperature of the water affect the rate and speed of the metal rusting?
Handout
Quiz
With their talk partners, the children are to go through the quiz at the end of the presentation and answer the questions.
Quiz in presentation
Can pupils identify familiar examples where materials are changing state?
Can pupils describe how specific materials have changed using scientific language? Can pupils identify and explain why some changes are permanent and some changes are non-permanent?
Quizzes in pupil zone.
Unit knowledge organiser and test available in unit documents area.
When does a Chemical Change happen?
What can affect a chemical change?
Whole Class Choral Response/suggested phrasing
A chemical change happens when…
Chemical changes can be affected by...
You can measure the rate of chemical change by...
The Science Behind the Science:
Chemical changes are difficult to reverse because the changes are occurring within the atoms themselves. When a chemical reaction takes place, you are left with the product(s). The end product is usually completely different to the starting product which is why these reactions are difficult to reverse. Chemical changes result in at least one new substance being formed. A very famous chemical change is combustion. In other words, when heat is applied to a chemical it is impossible to reverse the reaction. Unlike physical changes, chemical changes are very hard to see.
When a chemical reaction takes place, energy is used in the process. Without some sort of energy, there would be no reaction. This is needed because chemical compositions must be changed. The bonds within substances must be altered for effective change to take place. The molecular bonds are also changed when substances react with one another. All these changes lead to the permanent alteration of the molecule. During physical changes, the atoms stay bound to one another during their original molecular arrangement. These changes in chemical reactions. In other words, these types of reactions cannot be reversed. Different substances also have different reaction times which determines the rate of the chemical reaction taking place. Chemical changes can also cause physical changes, but physical changes cannot lead to chemical changes.
Demonstrate that dissolving, mixing and changes of state are reversible changes. Explain that some changes result in the formation of new materials and that this kind of change is not usually reversible, including changes associated with burning and the action of acid on bicarbonate of soda.
Materials - Chemical changes - Through experimentation, I can identify indicators of chemical reactions having occurred. I can describe ways of controlling the rate of reactions and can relate my findings to the world around me. SCN 3-19a
The study of the properties, behaviours and uses of materials, both natural and human made; the origins of human-made materials and how they are manipulated to suit a purpose.
Comparing and classifying
Reporting and presenting findings from enquiries, including conclusions, casual relationships and explanations of and degree of trust in results, inroad and written forms such as displays and other presentations.
Grade 6 - Sorting Materials into groups.
Grade 4 - Physical Science - Matter - Measuring Matter and Changes - How Matter Can Change - Definition of Chemical Changes ( Examples of Chemical changes, signs of chemical changes)
