reaction

A period with no sound or speech

A lack of response when something happens

As a response to something that happens

The body has a strong unwanted response to things like pollen or peanuts and causes swelling, sneezing and difficulty breathing

A change where substances turn into different substances

A process in which one nuclear event makes more nuclear events happen, keeping the reaction going

The time between seeing or hearing something and acting on it

A strong first feeling you have without thinking

A change inside an atom's core that makes or uses a large amount of energy

A chemical change that gives off heat to the area around it

A series of chemical or nuclear reactions in which one reaction makes the next start

A chemical change that takes in heat from the area around it

The body's defence that attacks foreign things like germs or transplanted organs

An automatic body response to something that affects it, like sweating or a faster heartbeat

A very hot reaction where parts of atoms join and make huge energy in stars or bombs

Bodily problems like paralysis or blindness that come from emotional stress and have no physical cause

A reaction where a more reactive element replaces a less reactive one in a compound

A strong feeling of worry that lasts a long time with physical signs like tension and shaking

Every push or pull makes an equal force in the opposite direction

A way a person acts without knowing to hide feelings by doing the opposite

A harmful response of the body after receiving the wrong blood from another person

A chemical reaction where one compound breaks into two or more different substances

A learned response that happens when a certain sound or signal appears, for example a dog drooling at a bell

A learned response that happens when a signal like a bell is paired with food many times

A reaction where one compound breaks into two or more simpler substances

A mental process done without thinking that reduces worry about uncomfortable feelings

A chemical change where two compounds exchange parts to make two new compounds

Two compounds swap ions to make two new compounds

A chemical reaction in which one molecule breaks into two smaller molecules by losing atoms or small groups

A reaction in the centre of an atom that takes in energy from around it

A chemical change in a living thing that proteins make happen faster

Two small molecules join to make a larger molecule

A quick increase in antibodies your body makes after it sees the same germ again

A chemical reaction where two small organic molecules join to make a larger molecule called an aldol

A nuclear reaction that gives off energy as heat or light

A way of acting you get from practice or experience

The first stage in plants' use of light to make energy molecules

A chemical test that shows a violet ring when sugars are present

An extreme response by the immune system to something you are allergic to that can be life threatening

A sudden drop in blood sugar after taking too much insulin

A reaction where an acid and a base make salt and water

A process where two atoms combine to make a heavier atom and give off energy

An action that keeps someone safe from danger

A lab test that shows a germ's outer layer swelling when antibodies are added

A machine like a jet or rocket that pushes a vehicle by throwing fast gas out the back

A machine that pushes a rocket or other spacecraft forward by shooting out fast gases

A way to move that rockets use by pushing out fast gas so the vehicle moves the other way

A machine with blades that makes power by using a fall in pressure along the blades with water or steam

A chemical change caused by light such as sunlight

A sudden large wave of comments from many people that follows an event

A quick change in your body and feelings when something suddenly surprises you, like a loud noise

A delayed reaction caused by the body's immune cells that appears hours after contact with something you are sensitive to

A very fast body reaction to something you are sensitive to, causing hives, itching, or very bad swelling

A blood test once used to check if someone had syphilis