Testable & Non-testable questions
Testable question - It is a question that can be answerd by an experiment. A testable question has 2 parts: an independent variable and dependent variable.
Independent variable - It is the variable that will be changed by you - the scientist. A good experiment has only one independent variable.
Dependent variable - It is the variable that is being measured in your experiment. The response to the change you make using the independent variable.
Non-testable question - Does not need an experiment.
Controlled variable - The only way to get reliable results from this experiment is to make sure that all the other variables stay the same, or controlled.
Harmful & Useful materials
Objects around us are made of different materials. The properties that these materials have help us understand why they are used for a specific purpose.
If objects are made ofthe right materials they will be useful. Transpareny, magnetic property, heat conductivity, flexibility, and electrical conductivity are some useful properties of materials.
Electric Conductors - Materials that have the ability to conduct electric current. Metals such as copper and silver are good conductors of electricity.
Electric Insulators - People use insulators to prevent them from being electrcuted when working with electrical wirings. Rubber, foam, and plastic are insulators.
Heat Conductors - For pots and kettles to be useful, they should be able to allow heat to pass through them quickly. They should be made of good conductors of heat so that the food cooks quickly. Steel, iron, aluminum, and other metals are good conductors of heat.
Heat Insulators - Materials that do not conduct heat but are useful are called insulators. They are used in handles of cooking utensils to protect us from getting burned.
Transparent materials - Allow light to pass through them. These are used to make objects that we can see through, such as windows. Materials that do not allow light to pass through them are said to be opaque.